JPS63315275A - Blurring-preventing mechanism for thermal transfer printer - Google Patents

Abstract

PURPOSE:To uncurl a medium and enable favorable printing, by printing on a medium by setting the medium on both a platen and an uncurling member fitted to a printer cover when the medium is thick. CONSTITUTION:An uncurling member 14 comprises a guide surface 14a parallel to a printing surface 11a of a platen 11, and is so provided that it can be detachably fitted to a printer cover 19 on the upper side of the platen 11. At the time of printing on a thick medium, the uncurling member 14 is fitted to the printer cover 19. Since the paper (thick medium) 100 is set on both the platen 11 and the uncurling member 14, a curl of the medium is straightened when the medium is positioned to a printing position of a thermal head 12 at the time of printing, resulting in favorable close contact of the medium with the platen 11. Therefore, favorable printing free of blurring can be achieved.

Description

[Detailed Description of the Invention] [Summary] The present invention is a thermal transfer printer that prints on a sheet of paper conveyed by a paper feed roller onto a platen using a thermal head facing the platen, which prints on thick media such as official postcards. A curling correction member is removably installed above the platen, and a thermal head presses the medium conveyed across the curling correction member and the platen during printing. This aims to achieve the objective by correcting medium curling.

[Industrial application field]

The present invention relates to a thermal transfer printer, and more particularly to a print blur prevention mechanism that can prevent print blur due to medium curling when printing on thick media such as government-made paper or paper.

Thermal transfer printers used for word processors, etc.
There is a type in which a thermal head facing the platen prints on the paper that is conveyed onto the platen by a paper feed roller. When printing on thick media such as official postcards with this type of thermal transfer printer, curling occurs on the media as it passes through the paper feed roller, which causes blurred printing, so take measures to prevent this. is an important issue.

[Conventional technology]

FIG. 4 is a side view showing the main structure of a conventional thermal transfer printer. In the figure, 1 is a platen, 2 is a thermal head, 3 is a paper feed roller, 4.5 is a pinch roller, and 6 is a paper guide.

The thermal head 2 is attached to a head carrier 7 and faces the platen 1, and the head carrier 7 is supported by a stay shaft 8 so as to be rotatable and slidable.

The paper (medium) 100 is guided by the paper guide 6 and supplied to the outer periphery of the paper feed roller 3 , and the rotation of the paper feed roller 3 causes the paper feed roller 3 and the pinch roller 4 . When the sheet is conveyed through the gap onto the printing surface la of the platen 1, and reaches a printing start state in which the leading edge passes the printing surface 1a by a predetermined distance, the sheet feeding roller 1 is temporarily stopped and sheet conveyance is stopped. In the case of the ink ribbon usage method, a ribbon cassette for storing the ink ribbon is mounted on the head carrier 7, and the ink ribbon fed out from the ribbon cassette is supplied between the paper 100 and the thermal head 2.

Printing starts from this state, and during printing, the thermal head 2 is moved through the paper 100 etc. to the platen 1 by the urging force of the spring 11 which urges the engagement plate 10 that fits into the slit 9 formed in the head carrier. Printing side 1
a, and while the thermal head 2 is spaced, the heating element formed on the surface of the thermal head 2 is energized in a predetermined pattern at a predetermined time to print. Note that in the case of the ink ribbon usage method, the ink ribbon is wound up at the same speed as the movement of the thermal head 2 so that relative movement in the space direction does not occur between the ink ribbon and the paper. Then, when the printing of the - line is completed, when the engaging plate 10 is rotated in the direction of the arrow against the urging force of the spring 11 by a driving means (not shown), the head carrier 7 is rotated clockwise and the thermal head 2 is rotated. Evacuate from platen 1. Next, the paper feed roller 3 is rotated by a predetermined amount to feed the paper 100, and the head carrier 7 is moved in the opposite direction to the original position, and the next line is printed using the same procedure as above. .

[Problem that the invention seeks to solve]

When printing on thick media such as official postcards using a thermal transfer printer having the above-described configuration 3, curling when the medium passes through the paper feed roller 3 makes it difficult for the medium to adhere to the platen 1, resulting in blurred printing. It's easy to happen.

In order to solve this problem, the following means can be considered.

■ Increase the diameter of the paper feed roller (approximately 20+ nm in diameter) to reduce curling.

■ Increase the head pressure (pressure force of the thermal head against the platen) to improve the adhesion between the medium and the platen.

However, with thermal transfer printers that do not satisfy these two points (older generation thermal transfer printers dedicated to thermal transfer paper), it is difficult to print well without blurring on thick media, and some countermeasure is required.

[Failure to solve the problem]

The present invention provides a printing blur prevention mechanism for a thermal transfer printer that can solve the above-mentioned problems, and the principle thereof is shown in FIG.

In FIG. 1, 11 is a platen, 12 is a thermal head, 13 is a paper feed roller, 14 is a curling correction member, and 100 is a medium.

The thermal head 12 is provided opposite to the platen 11 and has a printing position where it presses against the platen 11 and a print position where it presses against the platen 11.
It can be positioned to a retracted position.

The paper feed roller 13 is driven by a drive source (not shown) and rotates in the counterclockwise direction indicated by the arrow.

The curling correction member 14 is a part of the printing surface 11 of the platen 11.
It has a guide surface 14.2 parallel to a, and is removably attached to the printer cover 19 above the platen 11.

[Effect]

When printing on thick media, the curling correction member 14 is attached to the printer cover 19, and the paper feed roller 13
The medium 100 is conveyed and positioned at the printing start position to start printing. In this case, the paper 100 is placed on the platen 11
Since the medium straddles the curling correction member 14, curling of the medium is corrected when the thermal head 12 is positioned at the printing position during printing, and the close contact with the platen 11 is improved. Therefore, it is possible to perform good printing without misalignment.

〔Example〕

The present invention will now be described in detail with reference to FIGS. 2 and 3.

FIG. 2 is a side view showing the printing misregistration prevention mechanism of the thermal transfer printer according to the present invention. ).

The thermal head 12 is attached to a head carrier 15 and faces the platen 11, and the head carrier 15 is
It is rotatably and slidably supported by a stay shaft 16. A slit 17 is formed in the head carrier 15, and a retaining plate 18 is fitted into the slit 17.

The curling correction member 14 is a part of the printing surface 11 of the platen 11.
It has a guide surface 14a parallel to a, and is removably attached to the printer cover 19 above the platen 11. FIG. 3 shows how to attach the curling correction member 14 to the printer cover 19.

The paper 100 is guided by the paper guide 20 and supplied to the outer periphery of the paper feed roller 13 , and the rotation of the paper feed roller 13 causes the paper 100 to move between the paper feed roller 13 and the paper feed roller 1 .
When the sheet is conveyed through the pinch roller 21 that is in pressure contact with the paper feed roller 13 and reaches a position where the leading edge has passed a predetermined amount over the print surface 11a of the platen 11, the paper feed roller 13 is temporarily stopped and the paper conveyance is stopped. In this state, the leading end of the paper 100 straddles the platen 11 and the curling correction member 14.

Printing starts from this state, but during printing, the retaining plate 18 that fits into the slit 17 of the head carrier 15
The thermal head 12 is pressed against the printing surface 11a of the platen 11 by the biasing force of a spring (not shown) that biases the thermal head 12, and while the printing head 12 is moved in a space to the thermal head, a heating element formed on the surface is heated at a predetermined timing at a predetermined time. One line is printed by applying electricity in a pattern. Next, the holding plate 18 is moved in the direction of the arrow in FIG. 2 against the urging force of the spring.
This causes the head carrier 15 to rotate clockwise and the thermal head 12 to be retracted from the platen 11. In this state, the paper feed roller 13 feeds the paper 100, moves the head carrier 15 in the opposite direction to the original position, and presses the thermal head 12 again against the printing surface 11a to print the next line. , repeat this below. Note that the method using an ink ribbon is the same as the conventional method, so a description thereof will be omitted.

When the thermal head 12 is pressed against the printing surface 11a during printing, the paper 100 straddles the platen 11 and the curling correction member 14, so even if the paper is thick, curling of the medium is easily corrected, and the paper adheres tightly to the platen 11. Sexuality improves. Therefore, good printing without blurring is possible.

This effect can be expected even when the diameter of the paper feed roller 13 is not very large and the pressing force of the thermal head is not very large.The curling correction member 14 is not necessary when printing on thin paper, so in this case it is recommended to remove it. Make it.

〔Effect of the invention〕

As described above, according to the present invention, printing is performed by pressing the medium that straddles the platen and the curling correction member with the thermal printer, so even if the medium is thick, curling of the medium is corrected and printing is performed. This enables good printing without misalignment.

Furthermore, since the present invention uses a curling correction member that is detachable from the printer cover, it can be easily applied to existing thermal transfer printers.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the principle of the present invention. Fig. 2 is a side view showing a print blur prevention mechanism of a thermal transfer printer according to an embodiment of the present invention. Fig. 3 is a diagram showing how a curling correction member is attached to a printer cover according to an embodiment of the present invention. 4 is a side view showing the main structure of a conventional thermal transfer printer. In the figure, 11 is a platen, 11a is a printing surface, 12 is a thermal head, 13 is a paper feed roller, and 14 is a curling correction member. , 14a is a guide surface, 19 is a printer cover, and 100 is paper (medium). Fig. 1 is a diagram showing the principle of the present invention. Fig. 4 is a side view showing the main structure of a conventional thermal transfer printer.

Claims (1)

[Scope of Claims] A thermal transfer printer in which a thermal head (12) facing the platen (11) prints on a medium conveyed onto the platen (11) by a paper feed roller (13), the platen (11) A curling correction member (14) having a guide surface (14a) parallel to the printing surface (11a) of the printer cover (19) is placed above the platen (11).
) A print blur prevention mechanism for thermal transfer printers, which is removably installed.